On Mon, Jun 20, 2016 at 7:21 PM, Eric W. Biederman
<ebiederm@xxxxxxxxxxxx> wrote:
> Move the call of get_pid_ns, the call of proc_parse_options, and
> the setting of s_iflags into proc_fill_super so that mount_ns
> can be used.
>
> Convert proc_mount to call mount_ns and remove the now unnecessary
> code.
>
> Acked-by: Seth Forshee <seth.forshee@xxxxxxxxxxxxx>
> Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Reviewed-by: Djalal Harouni <tixxdz@xxxxxxxxx>
> ---
> fs/proc/inode.c | 9 +++++++--
> fs/proc/internal.h | 3 ++-
> fs/proc/root.c | 52 ++++------------------------------------------------
> 3 files changed, 13 insertions(+), 51 deletions(-)
>
> diff --git a/fs/proc/inode.c b/fs/proc/inode.c
> index 78fa452d65ed..f4817efb25a6 100644
> --- a/fs/proc/inode.c
> +++ b/fs/proc/inode.c
> @@ -457,12 +457,17 @@ struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de)
> return inode;
> }
>
> -int proc_fill_super(struct super_block *s)
> +int proc_fill_super(struct super_block *s, void *data, int silent)
> {
> + struct pid_namespace *ns = get_pid_ns(s->s_fs_info);
> struct inode *root_inode;
> int ret;
>
> - s->s_iflags |= SB_I_USERNS_VISIBLE;
> + if (!proc_parse_options(data, ns))
> + return -EINVAL;
> +
> + /* User space would break if executables appear on proc */
> + s->s_iflags |= SB_I_USERNS_VISIBLE | SB_I_NOEXEC;
> s->s_flags |= MS_NODIRATIME | MS_NOSUID | MS_NOEXEC;
> s->s_blocksize = 1024;
> s->s_blocksize_bits = 10;
> diff --git a/fs/proc/internal.h b/fs/proc/internal.h
> index aa2781095bd1..7931c558c192 100644
> --- a/fs/proc/internal.h
> +++ b/fs/proc/internal.h
> @@ -212,7 +212,7 @@ extern const struct inode_operations proc_pid_link_inode_operations;
>
> extern void proc_init_inodecache(void);
> extern struct inode *proc_get_inode(struct super_block *, struct proc_dir_entry *);
> -extern int proc_fill_super(struct super_block *);
> +extern int proc_fill_super(struct super_block *, void *data, int flags);
> extern void proc_entry_rundown(struct proc_dir_entry *);
>
> /*
> @@ -268,6 +268,7 @@ static inline void proc_tty_init(void) {}
> * root.c
> */
> extern struct proc_dir_entry proc_root;
> +extern int proc_parse_options(char *options, struct pid_namespace *pid);
>
> extern void proc_self_init(void);
> extern int proc_remount(struct super_block *, int *, char *);
> diff --git a/fs/proc/root.c b/fs/proc/root.c
> index a1b2860fec62..8d3e484055a6 100644
> --- a/fs/proc/root.c
> +++ b/fs/proc/root.c
> @@ -23,21 +23,6 @@
>
> #include "internal.h"
>
> -static int proc_test_super(struct super_block *sb, void *data)
> -{
> - return sb->s_fs_info == data;
> -}
> -
> -static int proc_set_super(struct super_block *sb, void *data)
> -{
> - int err = set_anon_super(sb, NULL);
> - if (!err) {
> - struct pid_namespace *ns = (struct pid_namespace *)data;
> - sb->s_fs_info = get_pid_ns(ns);
> - }
> - return err;
> -}
> -
> enum {
> Opt_gid, Opt_hidepid, Opt_err,
> };
> @@ -48,7 +33,7 @@ static const match_table_t tokens = {
> {Opt_err, NULL},
> };
>
> -static int proc_parse_options(char *options, struct pid_namespace *pid)
> +int proc_parse_options(char *options, struct pid_namespace *pid)
> {
> char *p;
> substring_t args[MAX_OPT_ARGS];
> @@ -100,45 +85,16 @@ int proc_remount(struct super_block *sb, int *flags, char *data)
> static struct dentry *proc_mount(struct file_system_type *fs_type,
> int flags, const char *dev_name, void *data)
> {
> - int err;
> - struct super_block *sb;
> struct pid_namespace *ns;
> - char *options;
>
> if (flags & MS_KERNMOUNT) {
> - ns = (struct pid_namespace *)data;
> - options = NULL;
> + ns = data;
> + data = NULL;
> } else {
> ns = task_active_pid_ns(current);
> - options = data;
> -
> - /* Does the mounter have privilege over the pid namespace? */
> - if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN))
> - return ERR_PTR(-EPERM);
> - }
> -
> - sb = sget(fs_type, proc_test_super, proc_set_super, flags, ns);
> - if (IS_ERR(sb))
> - return ERR_CAST(sb);
> -
> - if (!proc_parse_options(options, ns)) {
> - deactivate_locked_super(sb);
> - return ERR_PTR(-EINVAL);
> - }
> -
> - if (!sb->s_root) {
> - err = proc_fill_super(sb);
> - if (err) {
> - deactivate_locked_super(sb);
> - return ERR_PTR(err);
> - }
> -
> - sb->s_flags |= MS_ACTIVE;
> - /* User space would break if executables appear on proc */
> - sb->s_iflags |= SB_I_NOEXEC;
> }
>
> - return dget(sb->s_root);
> + return mount_ns(fs_type, flags, data, ns, ns->user_ns, proc_fill_super);
> }
>
> static void proc_kill_sb(struct super_block *sb)
> --
> 2.8.3
>
--
tixxdz
http://opendz.org
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